In the United States, myocardial ischemia is the underlying etiology in nearly 70% of the 5 million patients suffering from mechanical failure of the cardiac left ventricle (LV). Echocardiography (echo) is well suited for the analysis of LV function, however, the problem of conveying this clinically important information in a quantitative, objective, and reproducible manner persists. To address this problem and respond to the NIH PA-00-117 solicitation for innovations in biomedical information science and technology, the long-term goal of the proposed R21/R33 project is to develop methods for 1) quantitative and objective measurement of LV function, 2) reproducible diagnostic interpretation based on these measurements, and 3) standardized topologic mapping and parametric display of the results. We defined 3 parameters of LV function: 1) rate of local deformation (strain rate), 2) amplitude of deformation (strain), and 3) time interval to the transition (crossover) point of cyclic deformation. The practical implementation of the long-term objectives will be achieved through the development of a Multiparametric Computational Echo (MPCE) system. The main hypothesis of this R21/R33 project is that the MPCE system will a) precisely and accurately quantitate (R21 phase) and b) reproducibly clinically interpret (R33 phase) segmental LV function. This hypothesis will be tested on digital echo data from animal models and clinical cases of myocardial ischemia representing a wide range of segmental LV dysfunction. Specific Aims (R21 phase): Aim 1 - Develop algorithms for parametric analysis of local ventricular function (Year 1). Aim 2 - Test precision and accuracy of local LV functional analysis using MPCE (Year 2). Satisfaction of the predefined milestones will initiate the commencement of the R33 phase. Specific Aims (R33 phase): Aim 1 - Develop a neural network MPCE system and test it initially in animals (Year 3). Aim 2 - Refine parametric mapping and test reproducibility of MPCE data in humans (Year 4). Successful completion of this project will result in noninvasive, quantitative, objective, and reproducible interpretation of LV function, thus facilitating optimal diagnostic and therapeutic decisions in cardiology.